A continuing problem in care of large areas of cultivated vegetation is the difficulty of delivery of an agent such as a plant nutrient, fertilizer or a pesticide to the target. A practical and labor-saving approach to agent delivery in areas such as golf courses, parks, lawns, gardens and woodlands has been broadcast application of granular products containing an agent, for example via rotary spreader. Using granular products having particle sizes in the range of about 0.5 millimeter to about 10 millimeters, an operator can cover a large area with minimal distance traversed by the spreader itself, while applying the granular products relatively uniformly to the desired area.
A further efficiency of labor is realized when multiple substances useful to promote plant growth are applied simultaneously. Efforts to provide for simultaneous application of fertilizer and pesticide have resulted in a particle formulated to contain both fertilizer and pesticide components. U.S. Pat. Nos. 5,783,203; 5,830,576; 6,221,375 B1; 6,387,388 B1; 6,436,421 B1; and 7,018,643 B2 are exemplary of these efforts.
Unfortunately, the production of a dual action fertilizer-pesticide particle has proven to be only partially successful as a result of phytotoxic chemical burning associated with a hygroscopic fertilizer making a particle adherent towards foliage inducing phytotoxicity through pesticide exposure. Additionally, to manufacture such a particle is complicated owing to regulatory, seasonal, complicated production process requirements, and customer preferences as to the N-P-K fertilizer composition as well as differing environmental targets and/or treated area distribution requirements between components of the desired formulation. As a result, specialized batches of dual action single particles are problematic in tailoring variations based on the specific plant growth environment, infestations, or the like. These variations are either not met or create inventory problems and increase the cost of production.
Thus, there exists a need for a multiple effect mixture of different granule types to provide for the efficient broadcast of fertilizer and an active agent within a simple application while providing a simplified manufacturing and distribution process.